1. Field of the Invention
The present invention relates to products including power supply circuit boards, and particularly, relates to a product which includes a power supply circuit board having a power supply circuit electrically connected to a wireless communication circuit and which is used in an RFID (Radio Frequency Identification) system.
2. Description of the Related Art
In general, as a product management system, an RFID system includes a reader/writer which generates an induction field, and an IC tag (hereinafter referred to as a “wireless IC device”) which stores therein predetermined information regarding a product. This information is communicated between the reader/writer and the IC tag in a non-contact manner so that the information is transmitted. Examples of a wireless IC device used in an RFID system include devices disclosed in Japanese Unexamined Patent Application Publication No. 2005-136528 and Publication No. 2005-244778.
Specifically, a device including a plastic film 600, an antenna pattern 601 arranged on the plastic film 600, and a wireless IC chip 610 arranged on one end of the antenna pattern 601 as shown in FIG. 51, and a device including a plastic film 620, an antenna pattern 621 arranged on the plastic film 620, radiating electrodes 622 arranged on the plastic film 620, and a wireless IC chip 610 arranged on a predetermined portion of the antenna pattern 621 as shown in FIG. 52 have been proposed.
However, in the wireless IC devices in the related art, because the wireless IC chip 610 is arranged on each of the antenna patterns 601 and 621 using an Au bump so as to be electrically connected to each of the antenna patterns 601 and 621, the fine wireless IC chip 610 should be positioned on each of the films 600 and 620 having large areas. However, it is considerably difficult to implement the fine wireless IC chip 610 on each of the films 600 and 620 having large areas. That is, there arises a problem in that if positional deviation is generated in implementation, resonant frequency characteristics of the antennas can be changed. Furthermore, the resonant frequency characteristics of the antennas are also changed when the antenna pattern 601 and 621 are rolled or sandwiched between dielectric bodies (when the antenna pattern 601 or 621 is inserted into a book, for example).
Although the possibilities for use of such a wireless IC device are infinite, it is still difficult to arrange the wireless IC device on various products since resonant frequency characteristics are changed in accordance with an arrangement state of an antenna.